Escutcheon for shower arm



FIG. 1 is a pespective view of an escutcheon for shower arm showing my new design;

FIG. 2 is a side view thereof;

FIG. 3 is a front end view thereof; and,

FIG. 4 is a rear end view thereof.

The broken lines in the Figures are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for an escutcheon for shower arm, as shown and described. 